/*
 * @BEGIN LICENSE
 *
 * Psi4: an open-source quantum chemistry software package
 *
 * Copyright (c) 2007-2025 The Psi4 Developers.
 *
 * The copyrights for code used from other parties are included in
 * the corresponding files.
 *
 * This file is part of Psi4.
 *
 * Psi4 is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, version 3.
 *
 * Psi4 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with Psi4; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * @END LICENSE
 */

/*! \file
    \ingroup CCLAMBDA
    \brief Enter brief description of file here
*/
#include <cstdio>
#include "psi4/libdpd/dpd.h"
#include "MOInfo.h"
#include "Params.h"
#define EXTERN
#include "globals.h"

namespace psi {
namespace cclambda {

/* L2FL2(): Computes the contributions of the Fme HBAR matrix elements
** to the Lambda doubles equations.  These contributions are given in
** spin orbitals as:
**
** L_ij^ab <-- P(ij) P(ab) L_i^a Fjb
**
** where Fjb = fjb + t_n^f <jn||bf>
**
** TDC, July 2002
*/

void L1FL2(int L_irr) {
    int h, nirreps;
    int row, col;
    int i, j, a, b, I, J, A, B, Isym, Jsym, Asym, Bsym;
    dpdfile2 LIA, Lia, FJB, Fjb, L, F;
    dpdbuf4 newL2;

    nirreps = moinfo.nirreps;

    if (params.ref == 0) { /** RHF **/

        global_dpd_->file2_init(&L, PSIF_CC_LAMBDA, L_irr, 0, 1, "LIA");
        global_dpd_->file2_mat_init(&L);
        global_dpd_->file2_mat_rd(&L);
        global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 0, 1, "FME");
        global_dpd_->file2_mat_init(&F);
        global_dpd_->file2_mat_rd(&F);

        global_dpd_->buf4_init(&newL2, PSIF_CC_LAMBDA, L_irr, 0, 5, 0, 5, 0, "New LIjAb");

        for (h = 0; h < nirreps; h++) {
            global_dpd_->buf4_mat_irrep_init(&newL2, h);
            global_dpd_->buf4_mat_irrep_rd(&newL2, h);

            for (row = 0; row < newL2.params->rowtot[h]; row++) {
                i = newL2.params->roworb[h][row][0];
                j = newL2.params->roworb[h][row][1];

                for (col = 0; col < newL2.params->coltot[h ^ L_irr]; col++) {
                    a = newL2.params->colorb[h ^ L_irr][col][0];
                    b = newL2.params->colorb[h ^ L_irr][col][1];

                    I = L.params->rowidx[i];
                    Isym = L.params->psym[i];
                    J = F.params->rowidx[j];
                    Jsym = F.params->psym[j];
                    A = L.params->colidx[a];
                    Asym = L.params->qsym[a];
                    B = F.params->colidx[b];
                    Bsym = F.params->qsym[b];
                    if (((Isym ^ Asym) == L_irr) && (Jsym == Bsym))
                        newL2.matrix[h][row][col] += (L.matrix[Isym][I][A] * F.matrix[Jsym][J][B]);

                    if ((Isym == Asym) && ((Jsym ^ Bsym) == L_irr))
                        newL2.matrix[h][row][col] += (L.matrix[Jsym][J][B] * F.matrix[Isym][I][A]);
                }
            }

            global_dpd_->buf4_mat_irrep_wrt(&newL2, h);
            global_dpd_->buf4_mat_irrep_close(&newL2, h);
        }

        global_dpd_->buf4_close(&newL2);

        global_dpd_->file2_mat_close(&F);
        global_dpd_->file2_close(&F);
        global_dpd_->file2_mat_close(&L);
        global_dpd_->file2_close(&L);

    } else if (params.ref == 1) { /** ROHF **/

        global_dpd_->file2_init(&LIA, PSIF_CC_LAMBDA, L_irr, 0, 1, "LIA");
        global_dpd_->file2_mat_init(&LIA);
        global_dpd_->file2_mat_rd(&LIA);
        global_dpd_->file2_init(&Lia, PSIF_CC_LAMBDA, L_irr, 0, 1, "Lia");
        global_dpd_->file2_mat_init(&Lia);
        global_dpd_->file2_mat_rd(&Lia);
        global_dpd_->file2_init(&FJB, PSIF_CC_OEI, 0, 0, 1, "FME");
        global_dpd_->file2_mat_init(&FJB);
        global_dpd_->file2_mat_rd(&FJB);
        global_dpd_->file2_init(&Fjb, PSIF_CC_OEI, 0, 0, 1, "Fme");
        global_dpd_->file2_mat_init(&Fjb);
        global_dpd_->file2_mat_rd(&Fjb);
    } else if (params.ref == 2) { /** UHF **/

        global_dpd_->file2_init(&LIA, PSIF_CC_LAMBDA, L_irr, 0, 1, "LIA");
        global_dpd_->file2_mat_init(&LIA);
        global_dpd_->file2_mat_rd(&LIA);
        global_dpd_->file2_init(&Lia, PSIF_CC_LAMBDA, L_irr, 2, 3, "Lia");
        global_dpd_->file2_mat_init(&Lia);
        global_dpd_->file2_mat_rd(&Lia);
        global_dpd_->file2_init(&FJB, PSIF_CC_OEI, 0, 0, 1, "FME");
        global_dpd_->file2_mat_init(&FJB);
        global_dpd_->file2_mat_rd(&FJB);
        global_dpd_->file2_init(&Fjb, PSIF_CC_OEI, 0, 2, 3, "Fme");
        global_dpd_->file2_mat_init(&Fjb);
        global_dpd_->file2_mat_rd(&Fjb);
    }

    if (params.ref == 1) /** RHF/ROHF **/
        global_dpd_->buf4_init(&newL2, PSIF_CC_LAMBDA, L_irr, 2, 7, 2, 7, 0, "New LIJAB");
    else if (params.ref == 2) /** UHF **/
        global_dpd_->buf4_init(&newL2, PSIF_CC_LAMBDA, L_irr, 2, 7, 2, 7, 0, "New LIJAB");

    if (params.ref == 1 || params.ref == 2) {
        /* loop over row irreps of LIJAB */
        for (h = 0; h < nirreps; h++) {
            global_dpd_->buf4_mat_irrep_init(&newL2, h);
            global_dpd_->buf4_mat_irrep_rd(&newL2, h);

            /* loop over rows of irrep of LIJAB */
            for (row = 0; row < newL2.params->rowtot[h]; row++) {
                i = newL2.params->roworb[h][row][0];
                j = newL2.params->roworb[h][row][1];

                /* loop over cols of irrep of LIJAB */
                for (col = 0; col < newL2.params->coltot[h ^ L_irr]; col++) {
                    a = newL2.params->colorb[h ^ L_irr][col][0];
                    b = newL2.params->colorb[h ^ L_irr][col][1];

                    I = LIA.params->rowidx[i];
                    Isym = LIA.params->psym[i];
                    J = FJB.params->rowidx[j];
                    Jsym = FJB.params->psym[j];
                    A = LIA.params->colidx[a];
                    Asym = LIA.params->qsym[a];
                    B = FJB.params->colidx[b];
                    Bsym = FJB.params->qsym[b];

                    if (((Isym ^ Asym) == L_irr) && (Jsym == Bsym))
                        newL2.matrix[h][row][col] += (LIA.matrix[Isym][I][A] * FJB.matrix[Jsym][J][B]);

                    J = LIA.params->rowidx[j];
                    Jsym = LIA.params->psym[j];
                    I = FJB.params->rowidx[i];
                    Isym = FJB.params->psym[i];

                    if ((Isym == Asym) && ((Jsym ^ Bsym) == L_irr))
                        newL2.matrix[h][row][col] += (LIA.matrix[Jsym][J][B] * FJB.matrix[Isym][I][A]);

                    I = LIA.params->rowidx[i];
                    Isym = LIA.params->psym[i];
                    J = FJB.params->rowidx[j];
                    Jsym = FJB.params->psym[j];
                    B = LIA.params->colidx[b];
                    Bsym = LIA.params->qsym[b];
                    A = FJB.params->colidx[a];
                    Asym = FJB.params->qsym[a];

                    if (((Jsym ^ Asym) == L_irr) && (Isym == Bsym))
                        newL2.matrix[h][row][col] -= (LIA.matrix[Jsym][J][A] * FJB.matrix[Isym][I][B]);

                    J = LIA.params->rowidx[j];
                    Jsym = LIA.params->psym[j];
                    I = FJB.params->rowidx[i];
                    Isym = FJB.params->psym[i];

                    if ((Jsym == Asym) && ((Isym ^ Bsym) == L_irr))
                        newL2.matrix[h][row][col] -= (LIA.matrix[Isym][I][B] * FJB.matrix[Jsym][J][A]);
                }
            }

            global_dpd_->buf4_mat_irrep_wrt(&newL2, h);
            global_dpd_->buf4_mat_irrep_close(&newL2, h);
        }
        global_dpd_->buf4_close(&newL2);
    }

    if (params.ref == 1) /** RHF/ROHF **/
        global_dpd_->buf4_init(&newL2, PSIF_CC_LAMBDA, L_irr, 2, 7, 2, 7, 0, "New Lijab");
    else if (params.ref == 2) /** UHF **/
        global_dpd_->buf4_init(&newL2, PSIF_CC_LAMBDA, L_irr, 12, 17, 12, 17, 0, "New Lijab");

    if (params.ref == 1 || params.ref == 2) {
        for (h = 0; h < nirreps; h++) {
            global_dpd_->buf4_mat_irrep_init(&newL2, h);
            global_dpd_->buf4_mat_irrep_rd(&newL2, h);

            for (row = 0; row < newL2.params->rowtot[h]; row++) {
                i = newL2.params->roworb[h][row][0];
                j = newL2.params->roworb[h][row][1];

                for (col = 0; col < newL2.params->coltot[h ^ L_irr]; col++) {
                    a = newL2.params->colorb[h ^ L_irr][col][0];
                    b = newL2.params->colorb[h ^ L_irr][col][1];

                    I = Lia.params->rowidx[i];
                    Isym = Lia.params->psym[i];
                    J = Fjb.params->rowidx[j];
                    Jsym = Fjb.params->psym[j];
                    A = Lia.params->colidx[a];
                    Asym = Lia.params->qsym[a];
                    B = Fjb.params->colidx[b];
                    Bsym = Fjb.params->qsym[b];

                    if (((Isym ^ Asym) == L_irr) && (Jsym == Bsym))
                        newL2.matrix[h][row][col] += (Lia.matrix[Isym][I][A] * Fjb.matrix[Jsym][J][B]);

                    J = Lia.params->rowidx[j];
                    Jsym = Lia.params->psym[j];
                    I = Fjb.params->rowidx[i];
                    Isym = Fjb.params->psym[i];

                    if ((Isym == Asym) && ((Jsym ^ Bsym) == L_irr))
                        newL2.matrix[h][row][col] += (Lia.matrix[Jsym][J][B] * Fjb.matrix[Isym][I][A]);

                    I = Lia.params->rowidx[i];
                    Isym = Lia.params->psym[i];
                    J = Fjb.params->rowidx[j];
                    Jsym = Fjb.params->psym[j];
                    B = Lia.params->colidx[b];
                    Bsym = Lia.params->qsym[b];
                    A = Fjb.params->colidx[a];
                    Asym = Fjb.params->qsym[a];

                    if (((Jsym ^ Asym) == L_irr) && (Isym == Bsym))
                        newL2.matrix[h][row][col] -= (Lia.matrix[Jsym][J][A] * Fjb.matrix[Isym][I][B]);

                    J = Lia.params->rowidx[j];
                    Jsym = Lia.params->psym[j];
                    I = Fjb.params->rowidx[i];
                    Isym = Fjb.params->psym[i];

                    if ((Jsym == Asym) && ((Isym ^ Bsym) == L_irr))
                        newL2.matrix[h][row][col] -= (Lia.matrix[Isym][I][B] * Fjb.matrix[Jsym][J][A]);
                }
            }

            global_dpd_->buf4_mat_irrep_wrt(&newL2, h);
            global_dpd_->buf4_mat_irrep_close(&newL2, h);
        }
        global_dpd_->buf4_close(&newL2);
    }

    if (params.ref == 1) /** RHF/ROHF **/
        global_dpd_->buf4_init(&newL2, PSIF_CC_LAMBDA, L_irr, 0, 5, 0, 5, 0, "New LIjAb");
    else if (params.ref == 2) /** UHF **/
        global_dpd_->buf4_init(&newL2, PSIF_CC_LAMBDA, L_irr, 22, 28, 22, 28, 0, "New LIjAb");

    if (params.ref == 1 || params.ref == 2) {
        for (h = 0; h < nirreps; h++) {
            global_dpd_->buf4_mat_irrep_init(&newL2, h);
            global_dpd_->buf4_mat_irrep_rd(&newL2, h);

            for (row = 0; row < newL2.params->rowtot[h]; row++) {
                i = newL2.params->roworb[h][row][0];
                j = newL2.params->roworb[h][row][1];

                for (col = 0; col < newL2.params->coltot[h ^ L_irr]; col++) {
                    a = newL2.params->colorb[h ^ L_irr][col][0];
                    b = newL2.params->colorb[h ^ L_irr][col][1];

                    I = LIA.params->rowidx[i];
                    Isym = LIA.params->psym[i];
                    J = Fjb.params->rowidx[j];
                    Jsym = Fjb.params->psym[j];
                    A = LIA.params->colidx[a];
                    Asym = LIA.params->qsym[a];
                    B = Fjb.params->colidx[b];
                    Bsym = Fjb.params->qsym[b];

                    if (((Isym ^ Asym) == L_irr) && (Jsym == Bsym))
                        newL2.matrix[h][row][col] += (LIA.matrix[Isym][I][A] * Fjb.matrix[Jsym][J][B]);

                    J = Lia.params->rowidx[j];
                    Jsym = Lia.params->psym[j];
                    I = FJB.params->rowidx[i];
                    Isym = FJB.params->psym[i];
                    B = Lia.params->colidx[b];
                    Bsym = Lia.params->qsym[b];
                    A = FJB.params->colidx[a];
                    Asym = FJB.params->qsym[a];

                    if ((Isym == Asym) && ((Jsym ^ Bsym) == L_irr))
                        newL2.matrix[h][row][col] += (Lia.matrix[Jsym][J][B] * FJB.matrix[Isym][I][A]);
                }
            }

            global_dpd_->buf4_mat_irrep_wrt(&newL2, h);
            global_dpd_->buf4_mat_irrep_close(&newL2, h);
        }
    }

    if (params.ref == 1 || params.ref == 2) {
        global_dpd_->buf4_close(&newL2);

        global_dpd_->file2_mat_close(&FJB);
        global_dpd_->file2_close(&FJB);
        global_dpd_->file2_mat_close(&Fjb);
        global_dpd_->file2_close(&Fjb);
        global_dpd_->file2_mat_close(&LIA);
        global_dpd_->file2_close(&LIA);
        global_dpd_->file2_mat_close(&Lia);
        global_dpd_->file2_close(&Lia);
    }
}

}  // namespace cclambda
}  // namespace psi
